Skydive Tecumseh is a proud member of the USPA
Wonderful staff -- my tandem instructor, James, was funny, clear, and made sure that I was comfortable during the entire experience (which involved two flights and a bit of "will-we-or-won't-we" due to clouds).
The dive itself is unreal -- exhilarating and meditative, terrifying and relaxing, absolutely breathtaking. I absolutely recommend you try it here first. Skydive Tecumseh has a great reputation, and there's a reason for that. I hope to go again.